Method and apparatus for receiving or transmitting downlink signal in wireless communication system

ABSTRACT

According to one embodiment of the present invention, a method of decoding, by a user equipment, a downlink signal in a wireless communication system comprises the steps of: receiving a semi-persistent zero power-channel state information reference signal (SP ZP CSI-RS) resource configuration from a base station; and decoding a downlink signal according to the SP ZP CSI-RS resource configuration. The SP ZP CSI-RS resource configuration includes a plurality of SP ZP CSI-RS resources and information on whether or not each of a plurality of the SP ZP CSI-RS resources is used can be indicated or configured by the base station.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/065,383, filed on Dec. 14, 2018, now allowed, which is a NationalStage application under 35 U.S.C. § 371 of International Application No.PCT/KR2018/002646, filed on Mar. 6, 2018, which claims the benefit ofU.S. Provisional Application No. 62/519,877, filed on Jun. 15, 2017,U.S. Provisional Application No. 62/490,602, filed on Apr. 27, 2017, andU.S. Provisional Application No. 62/467,248, filed on Mar. 6, 2017. Thedisclosures of the prior applications are incorporated by reference intheir entirety.

TECHNICAL FIELD

The present invention relates to a wireless communication system, andmore particularly, to a method of receiving or transmitting a downlinksignal in a wireless communication system and an apparatus therefor.

BACKGROUND ART

As more communication devices require greater communication traffic,necessity for a mobile broadband communication, which is enhancedcompared to a legacy radio access technology (RAT), is emerging. MassiveMTC (machine type communication) providing a user with various servicesanywhere and at any time by connecting many devices and objects is oneof important issues to be considered in the next generationcommunication system. Moreover, discussion on designing a communicationsystem in consideration of a service sensitive to reliability andlatency is in progress. In particular, discussion on the introduction ofa next generation RAT considering eMBB (enhanced mobile broadbandcommunication), massive MTC (mMTC), URLLC (ultra-reliable and lowlatency communication), and the like is in progress. In the presentinvention, for clarity, the next generation RAT is referred to as a NewRAT.

DISCLOSURE OF THE INVENTION Technical Task

A technical task of the present invention is to provide a method ofreceiving or transmitting a downlink signal. More specifically, atechnical task of the present invention is to provide a method ofreceiving or transmitting a configuration related to rate matching of abase station or a user equipment, a method of signaling theconfiguration, and a method of receiving or transmitting a downlinksignal based on the signaling.

Technical tasks obtainable from the present invention are non-limitedthe above-mentioned technical task. And, other unmentioned technicaltasks can be clearly understood from the following description by thosehaving ordinary skill in the technical field to which the presentinvention pertains.

Technical Solution

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, accordingto one embodiment, a method for decoding a downlink signal, which isdecoded by a terminal in a wireless communication system, includesreceiving a semi-persistent zero power-channel state informationreference signal (SP ZP CSI-RS) resource configuration from a basestation, and decoding a downlink signal according to the SP ZP CSI-RSresource configuration. In this case, the SP ZP CSI-RS resourceconfiguration includes a plurality of SP ZP CSI-RS resources andinformation on whether or not each of SP ZP CSI-RS resources is used maybe indicated or configured by the base station.

Additionally or alternatively, the SP ZP CSI-RS resource configurationmay be independent of a resource configuration for performingmeasurement of the terminal.

Additionally or alternatively, the method may further include performingrate matching in an SP ZP CSI-RS resource enabled by a period and anoffset indicated by the SP ZP CSI-RS resource configuration according tothe SP ZP CSI-RS resource configuration.

Additionally or alternatively, a signal for enabling or disabling the SPZP CSI-RS resource may include DCI (downlink control information) or MAC(medium access control) signaling.

Additionally or alternatively, each of the SP ZP CSI-RS resources mayhave a frequency configuration.

Additionally or alternatively, the frequency configuration may beprovided by a separate signaling from the SP ZP CSI-RS resourceconfiguration.

Additionally or alternatively, each of the SP ZP CSI-RS resources isassociated with a respective one of transmission beams used by the basestation and an SP ZP CSI-RS resource associated with the transmissionbeam can be used for decoding the downlink signal.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, according to a different embodiment, aterminal for decoding a downlink signal in a wireless communicationsystem includes a transmitter and a receiver and a processor thatcontrols the transmitter and the receiver, the processor receives asemi-persistent zero power-channel state information reference signal(SP ZP CSI-RS) resource configuration from a base station, decodes adownlink signal according to the SP ZP CSI-RS resource configuration. Inthis case, the SP ZP CSI-RS resource configuration may include aplurality of SP ZP CSI-RS resources and information on whether or noteach of SP ZP CSI-RS resources is used may be indicated or configured bythe base station.

Additionally or alternatively, the SP ZP CSI-RS resource configurationmay be independent of a resource configuration for performingmeasurement of the terminal.

Additionally or alternatively, the processor may perform rate matchingin an SP ZP CSI-RS resource enabled by a period and an offset indicatedby the SP ZP CSI-RS resource configuration according to the SP ZP CSI-RSresource configuration.

Additionally or alternatively, a signal for enabling or disabling the SPZP CSI-RS resource may include DCI (downlink control information) or MAC(medium access control) signaling.

Additionally or alternatively, each of the SP ZP CSI-RS resources mayhave a frequency configuration.

Additionally or alternatively, the frequency configuration may beprovided by a separate signaling from the SP ZP CSI-RS resourceconfiguration.

Additionally or alternatively, each of the SP ZP CSI-RS resources may beassociated with a respective one of transmission beams used by the basestation and an SP ZP CSI-RS resource associated with the transmissionbeam can be used for decoding the downlink signal.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, according to a further differentembodiment, a method of transmitting a downlink signal, which istransmitted by a base station in a wireless communication system,includes the steps of transmitting a semi-persistent zero power-channelstate information reference signal (SP ZP CSI-RS) resource configurationto a terminal, and mapping resource elements for a downlink signalaccording to the SP ZP CSI-RS resource configuration and transmittingthe downlink signal. In this case, the SP ZP CSI-RS resourceconfiguration may include a plurality of SP ZP CSI-RS resources and asignaling indicating or configuring information on whether or not an SPZP CSI-RS resource is used may be transmitted to the terminal.

Technical solutions obtainable from the present invention arenon-limited the above-mentioned technical solutions. And, otherunmentioned technical solutions can be clearly understood from thefollowing description by those having ordinary skill in the technicalfield to which the present invention pertains.

Advantageous Effects

According to the present invention, it is able to efficiently performdownlink reception.

Effects obtainable from the present invention may be non-limited by theabove mentioned effect. And, other unmentioned effects can be clearlyunderstood from the following description by those having ordinary skillin the technical field to which the present invention pertains

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a diagram for an example of a radio frame structure used in awireless communication system;

FIG. 2 is a diagram for an example of a downlink (DL)/uplink (UL) slotstructure in a wireless communication system;

FIG. 3 is a diagram for an example of a downlink (DL) subframe structureused in 3GPP LTE/LTE-A system;

FIG. 4 is a diagram for an example of an uplink (UL) subframe structureused in 3GPP LTE/LTE-A system;

FIG. 5 illustrates a rate matching setting having a sharing resourcesetting with a ZP-CSI-RS resource;

FIG. 6 illustrates a rate matching setting having a resource settingindependent of a ZP-CSI-RS resource configuration;

FIG. 7 illustrates a ZP-CSI-RS configuration for performing ratematching included in a measurement setting;

FIG. 8 illustrates an example of allocating a rate matching setting to aresource setting;

FIGS. 9 to 17 illustrate examples of payload of control information forperforming rate matching according to one embodiment of the presentinvention;

FIG. 18 is a diagram for explaining a relationship between atransmission beam and a rate matching resource;

FIG. 19 is a block diagram of a device for implementing embodiment(s) ofthe present invention.

BEST MODE Mode for Invention

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The accompanying drawings illustrate exemplary embodiments ofthe present invention and provide a more detailed description of thepresent invention. However, the scope of the present invention shouldnot be limited thereto.

In some cases, to prevent the concept of the present invention frombeing ambiguous, structures and apparatuses of the known art will beomitted, or will be shown in the form of a block diagram based on mainfunctions of each structure and apparatus. Also, wherever possible, thesame reference numbers will be used throughout the drawings and thespecification to refer to the same or like parts.

In the present invention, a user equipment (UE) is fixed or mobile. TheUE is a device that transmits and receives user data and/or controlinformation by communicating with a base station (BS). The term ‘UE’ maybe replaced with ‘terminal equipment’, ‘Mobile Station (MS)’, ‘MobileTerminal (MT)’, ‘User Terminal (UT)’, ‘Subscriber Station (SS)’,‘wireless device’, ‘Personal Digital Assistant (PDA)’, ‘wireless modem’,‘handheld device’, etc. ABS is typically a fixed station thatcommunicates with a UE and/or another BS. The BS exchanges data andcontrol information with a UE and another BS. The term ‘BS’ may bereplaced with ‘Advanced Base Station (ABS)’, ‘Node B’, ‘evolved-Node B(eNB)’, ‘Base Transceiver System (BTS)’, ‘Access Point (AP)’,‘Processing Server (PS)’, etc. In the following description, BS iscommonly called eNB.

In the present invention, a node refers to a fixed point capable oftransmitting/receiving a radio signal to/from a UE by communication withthe UE. Various eNBs can be used as nodes. For example, a node can be aBS, NB, eNB, pico-cell eNB (PeNB), home eNB (HeNB), relay, repeater,etc. Furthermore, a node may not be an eNB. For example, a node can be aradio remote head (RRH) or a radio remote unit (RRU). The RRH and RRUhave power levels lower than that of the eNB. Since the RRH or RRU(referred to as RRH/RRU hereinafter) is connected to an eNB through adedicated line such as an optical cable in general, cooperativecommunication according to RRH/RRU and eNB can be smoothly performedcompared to cooperative communication according to eNBs connectedthrough a wireless link. At least one antenna is installed per node. Anantenna may refer to an antenna port, a virtual antenna or an antennagroup. A node may also be called a point. Unlike a conventionalcentralized antenna system (CAS) (i.e. single node system) in whichantennas are concentrated in an eNB and controlled an eNB controller,plural nodes are spaced apart at a predetermined distance or longer in amulti-node system. The plural nodes can be managed by one or more eNBsor eNB controllers that control operations of the nodes or schedule datato be transmitted/received through the nodes. Each node may be connectedto an eNB or eNB controller managing the corresponding node via a cableor a dedicated line. In the multi-node system, the same cell identity(ID) or different cell IDs may be used for signal transmission/receptionthrough plural nodes. When plural nodes have the same cell ID, each ofthe plural nodes operates as an antenna group of a cell. If nodes havedifferent cell IDs in the multi-node system, the multi-node system canbe regarded as a multi-cell (e.g., macro-cell/femto-cell/pico-cell)system. When multiple cells respectively configured by plural nodes areoverlaid according to coverage, a network configured by multiple cellsis called a multi-tier network. The cell ID of the RRH/RRU may beidentical to or different from the cell ID of an eNB. When the RRH/RRUand eNB use different cell IDs, both the RRH/RRU and eNB operate asindependent eNBs.

In a multi-node system according to the present invention, which will bedescribed below, one or more eNBs or eNB controllers connected to pluralnodes can control the plural nodes such that signals are simultaneouslytransmitted to or received from a UE through some or all nodes. Whilethere is a difference between multi-node systems according to the natureof each node and implementation form of each node, multi-node systemsare discriminated from single node systems (e.g. CAS, conventional MIMOsystems, conventional relay systems, conventional repeater systems,etc.) since a plurality of nodes provides communication services to a UEin a predetermined time-frequency resource. Accordingly, embodiments ofthe present invention with respect to a method of performing coordinateddata transmission using some or all nodes can be applied to varioustypes of multi-node systems. For example, a node refers to an antennagroup spaced apart from another node by a predetermined distance ormore, in general. However, embodiments of the present invention, whichwill be described below, can even be applied to a case in which a noderefers to an arbitrary antenna group irrespective of node interval. Inthe case of an eNB including an X-pole (cross polarized) antenna, forexample, the embodiments of the preset invention are applicable on theassumption that the eNB controls a node composed of an H-pole antennaand a V-pole antenna.

A communication scheme through which signals are transmitted/receivedvia plural transmit (Tx)/receive (Rx) nodes, signals aretransmitted/received via at least one node selected from plural Tx/Rxnodes, or a node transmitting a downlink signal is discriminated from anode transmitting an uplink signal is called multi-eNB MIMO or CoMP(Coordinated Multi-Point Tx/Rx). Coordinated transmission schemes fromamong CoMP communication schemes can be categorized into JP (JointProcessing) and scheduling coordination. The former may be divided intoJT (Joint Transmission)/JR (Joint Reception) and DPS (Dynamic PointSelection) and the latter may be divided into CS (CoordinatedScheduling) and CB (Coordinated Beamforming). DPS may be called DCS(Dynamic Cell Selection). When JP is performed, more variouscommunication environments can be generated, compared to other CoMPschemes. JT refers to a communication scheme by which plural nodestransmit the same stream to a UE and JR refers to a communication schemeby which plural nodes receive the same stream from the UE. The UE/eNBcombine signals received from the plural nodes to restore the stream. Inthe case of JT/JR, signal transmission reliability can be improvedaccording to transmit diversity since the same stream is transmittedfrom/to plural nodes. DPS refers to a communication scheme by which asignal is transmitted/received through a node selected from plural nodesaccording to a specific rule. In the case of DPS, signal transmissionreliability can be improved because a node having a good channel statebetween the node and a UE is selected as a communication node.

In the present invention, a cell refers to a specific geographical areain which one or more nodes provide communication services. Accordingly,communication with a specific cell may mean communication with an eNB ora node providing communication services to the specific cell. Adownlink/uplink signal of a specific cell refers to a downlink/uplinksignal from/to an eNB or a node providing communication services to thespecific cell. A cell providing uplink/downlink communication servicesto a UE is called a serving cell. Furthermore, channel status/quality ofa specific cell refers to channel status/quality of a channel or acommunication link generated between an eNB or a node providingcommunication services to the specific cell and a UE. In 3GPP LTE-Asystems, a UE can measure downlink channel state from a specific nodeusing one or more CSI-RSs (Channel State Information Reference Signals)transmitted through antenna port(s) of the specific node on a CSI-RSresource allocated to the specific node. In general, neighboring nodestransmit CSI-RS resources on orthogonal CSI-RS resources. When CSI-RSresources are orthogonal, this means that the CSI-RS resources havedifferent subframe configurations and/or CSI-RS sequences which specifysubframes to which CSI-RSs are allocated according to CSI-RS resourceconfigurations, subframe offsets and transmission periods, etc. whichspecify symbols and subcarriers carrying the CSI RSs.

In the present invention, PDCCH (Physical Downlink ControlChannel)/PCFICH (Physical Control Format Indicator Channel)/PHICH(Physical Hybrid automatic repeat request Indicator Channel)/PDSCH(Physical Downlink Shared Channel) refer to a set of time-frequencyresources or resource elements respectively carrying DCI (DownlinkControl Information)/CFI (Control Format Indicator)/downlink ACK/NACK(Acknowledgement/Negative ACK)/downlink data. In addition, PUCCH(Physical Uplink Control Channel)/PUSCH (Physical Uplink SharedChannel)/PRACH (Physical Random Access Channel) refer to sets oftime-frequency resources or resource elements respectively carrying UCI(Uplink Control Information)/uplink data/random access signals. In thepresent invention, a time-frequency resource or a resource element (RE),which is allocated to or belongs toPDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH, is referred to as aPDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH RE orPDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH resource. In the followingdescription, transmission of PUCCH/PUSCH/PRACH by a UE is equivalent totransmission of uplink control information/uplink data/random accesssignal through or on PUCCH/PUSCH/PRACH. Furthermore, transmission ofPDCCH/PCFICH/PHICH/PDSCH by an eNB is equivalent to transmission ofdownlink data/control information through or onPDCCH/PCFICH/PHICH/PDSCH.

FIG. 1 illustrates an exemplary radio frame structure used in a wirelesscommunication system. FIG. 1(a) illustrates a frame structure forfrequency division duplex (FDD) used in 3GPP LTE/LTE-A and FIG. 1(b)illustrates a frame structure for time division duplex (TDD) used in3GPP LTE/LTE-A.

Referring to FIG. 1, a radio frame used in 3GPP LTE/LTE-A has a lengthof 10 ms (307200 Ts) and includes 10 subframes in equal size. The 10subframes in the radio frame may be numbered. Here, Ts denotes samplingtime and is represented as Ts=1/(2048*15 kHz). Each subframe has alength of 1 ms and includes two slots. 20 slots in the radio frame canbe sequentially numbered from 0 to 19. Each slot has a length of 0.5 ms.A time for transmitting a subframe is defined as a transmission timeinterval (TTI). Time resources can be discriminated by a radio framenumber (or radio frame index), subframe number (or subframe index) and aslot number (or slot index).

The radio frame can be configured differently according to duplex mode.Downlink transmission is discriminated from uplink transmission byfrequency in FDD mode, and thus the radio frame includes only one of adownlink subframe and an uplink subframe in a specific frequency band.In TDD mode, downlink transmission is discriminated from uplinktransmission by time, and thus the radio frame includes both a downlinksubframe and an uplink subframe in a specific frequency band.

Table 1 shows DL-UL configurations of subframes in a radio frame in theTDD mode.

TABLE 1 DL-UL Downlink-to- config- Uplink Switch- Subframe numberuration point periodicity 0 1 2 3 4 5 6 7 8 9 0  5 ms D S U U U D S U UU 1  5 ms D S U U D D S U U D 2  5 ms D S U D D D S U D D 3 10 ms D S UU U D D D D D 4 10 ms D S U U D D D D D D 5 10 ms D S U D D D D D D D 6 5 ms D S U U U D S U U D

In Table 1, D denotes a downlink subframe, U denotes an uplink subframeand S denotes a special subframe. The special subframe includes threefields of DwPTS (Downlink Pilot TimeSlot), GP (Guard Period), and UpPTS(Uplink Pilot TimeSlot). DwPTS is a period reserved for downlinktransmission and UpPTS is a period reserved for uplink transmission.Table 2 shows special subframe configuration.

TABLE 2 Normal cyclic prefix in downlink Extended cyclic prefix indownlink UpPTS UpPTS Normal Extended Normal Extended Special cycliccyclic cyclic cyclic subframe prefix in prefix in prefix in prefix inconfiguration DwPTS uplink uplink DwPTS uplink uplink 0  6592 · T_(s)2192 · T_(s) 2560 · T_(s)  7680 · T_(s) 2192 · T_(s) 2560 · T_(s) 119760 · T_(s) 20480 · T_(s) 2 21952 · T_(s) 23040 · T_(s) 3 24144 ·T_(s) 25600 · T_(s) 4 26336 · T_(s)  7680 · T_(s) 4384 · T_(s) 5120 ·T_(s) 5  6592 · T_(s) 4384 · T_(s) 5120 · T_(s) 20480 · T_(s) 6 19760 ·T_(s) 23040 · T_(s) 7 21952 · T_(s) 12800 · T_(s) 8 24144 · T_(s) — — —9 13168 · T_(s) — — —

FIG. 2 illustrates an exemplary downlink/uplink slot structure in awireless communication system. Particularly, FIG. 2 illustrates aresource grid structure in 3GPP LTE/LTE-A. A resource grid is presentper antenna port.

Referring to FIG. 2, a slot includes a plurality of OFDM (OrthogonalFrequency Division Multiplexing) symbols in the time domain and aplurality of resource blocks (RBs) in the frequency domain. An OFDMsymbol may refer to a symbol period. A signal transmitted in each slotmay be represented by a resource grid composed of N_(RB) ^(DL/UL)*N_(sc)^(RB) subcarriers and N_(symb) ^(DL/UL) OFDM symbols. Here, N_(RB) ^(DL)denotes the number of RBs in a downlink slot and N_(RB) ^(UL) denotesthe number of RBs in an uplink slot. N_(RB) ^(DL) and N_(RB) ^(UL)respectively depend on a DL transmission bandwidth and a UL transmissionbandwidth. N_(symb) ^(DL) denotes the number of OFDM symbols in thedownlink slot and N_(symb) ^(UL) denotes the number of OFDM symbols inthe uplink slot. In addition, N_(sc) ^(RB) denotes the number ofsubcarriers constructing one RB.

An OFDM symbol may be called an SC-FDM (Single Carrier FrequencyDivision Multiplexing) symbol according to multiple access scheme. Thenumber of OFDM symbols included in a slot may depend on a channelbandwidth and the length of a cyclic prefix (CP). For example, a slotincludes 7 OFDM symbols in the case of normal CP and 6 OFDM symbols inthe case of extended CP. While FIG. 2 illustrates a subframe in which aslot includes 7 OFDM symbols for convenience, embodiments of the presentinvention can be equally applied to subframes having different numbersof OFDM symbols. Referring to FIG. 2, each OFDM symbol includes N_(RB)^(DL/UL)*N_(sc) ^(RB) subcarriers in the frequency domain. Subcarriertypes can be classified into a data subcarrier for data transmission, areference signal subcarrier for reference signal transmission, and nullsubcarriers for a guard band and a direct current (DC) component. Thenull subcarrier for a DC component is a subcarrier remaining unused andis mapped to a carrier frequency (f0) during OFDM signal generation orfrequency up-conversion. The carrier frequency is also called a centerfrequency.

An RB is defined by N_(symb) ^(DL/UL) (e.g., 7) consecutive OFDM symbolsin the time domain and N_(sc) ^(RB) (e.g., 12) consecutive subcarriersin the frequency domain. For reference, a resource composed by an OFDMsymbol and a subcarrier is called a resource element (RE) or a tone.Accordingly, an RB is composed of N_(symb) ^(DL/UL)*N_(sc) ^(RB) REs.Each RE in a resource grid can be uniquely defined by an index pair(k, 1) in a slot. Here, k is an index in the range of 0 to N_(symb)^(DL/UL)*N_(sc) ^(RB)−1 in the frequency domain and 1 is an index in therange of 0 to N_(symb) ^(DL/UL)−1.

Two RBs that occupy N_(sc) ^(RB) consecutive subcarriers in a subframeand respectively disposed in two slots of the subframe are called aphysical resource block (PRB) pair. Two RBs constituting a PRB pair havethe same PRB number (or PRB index). A virtual resource block (VRB) is alogical resource allocation unit for resource allocation. The VRB hasthe same size as that of the PRB. The VRB may be divided into alocalized VRB and a distributed VRB depending on a mapping scheme of VRBinto PRB. The localized VRBs are mapped into the PRBs, whereby VRBnumber (VRB index) corresponds to PRB number. That is, nPRB=nVRB isobtained. Numbers are given to the localized VRBs from 0 to N_(VRB)^(DL)−1, and N_(VRB) ^(DL)=N_(RB) ^(DL) is obtained. Accordingly,according to the localized mapping scheme, the VRBs having the same VRBnumber are mapped into the PRBs having the same PRB number at the firstslot and the second slot. On the other hand, the distributed VRBs aremapped into the PRBs through interleaving. Accordingly, the VRBs havingthe same VRB number may be mapped into the PRBs having different PRBnumbers at the first slot and the second slot. Two PRBs, which arerespectively located at two slots of the subframe and have the same VRBnumber, will be referred to as a pair of VRBs.

FIG. 3 illustrates a downlink (DL) subframe structure used in 3GPPLTE/LTE-A.

Referring to FIG. 3, a DL subframe is divided into a control region anda data region. A maximum of three (four) OFDM symbols located in a frontportion of a first slot within a subframe correspond to the controlregion to which a control channel is allocated. A resource regionavailable for PDCCH transmission in the DL subframe is referred to as aPDCCH region hereinafter. The remaining OFDM symbols correspond to thedata region to which a physical downlink shared chancel (PDSCH) isallocated. A resource region available for PDSCH transmission in the DLsubframe is referred to as a PDSCH region hereinafter. Examples ofdownlink control channels used in 3GPP LTE include a physical controlformat indicator channel (PCFICH), a physical downlink control channel(PDCCH), a physical hybrid ARQ indicator channel (PHICH), etc. ThePCFICH is transmitted at a first OFDM symbol of a subframe and carriesinformation regarding the number of OFDM symbols used for transmissionof control channels within the subframe. The PHICH is a response ofuplink transmission and carries an HARQ acknowledgment (ACK)/negativeacknowledgment (NACK) signal.

Control information carried on the PDCCH is called downlink controlinformation (DCI). The DCI contains resource allocation information andcontrol information for a UE or a UE group. For example, the DCIincludes a transport format and resource allocation information of adownlink shared channel (DL-SCH), a transport format and resourceallocation information of an uplink shared channel (UL-SCH), paginginformation of a paging channel (PCH), system information on the DL-SCH,information about resource allocation of an upper layer control messagesuch as a random access response transmitted on the PDSCH, a transmitcontrol command set with respect to individual UEs in a UE group, atransmit power control command, information on activation of a voiceover IP (VoIP), downlink assignment index (DAI), etc. The transportformat and resource allocation information of the DL-SCH are also calledDL scheduling information or a DL grant and the transport format andresource allocation information of the UL-SCH are also called ULscheduling information or a UL grant. The size and purpose of DCIcarried on a PDCCH depend on DCI format and the size thereof may bevaried according to coding rate. Various formats, for example, formats 0and 4 for uplink and formats 1, 1A, 1B, 1C, 1D, 2, 2A, 2B, 2C, 3 and 3Afor downlink, have been defined in 3GPP LTE. Control information such asa hopping flag, information on RB allocation, modulation coding scheme(MCS), redundancy version (RV), new data indicator (NDI), information ontransmit power control (TPC), cyclic shift demodulation reference signal(DMRS), UL index, channel quality information (CQI) request, DLassignment index, HARQ process number, transmitted precoding matrixindicator (TPMI), precoding matrix indicator (PMI), etc. is selected andcombined based on DCI format and transmitted to a UE as DCI.

In general, a DCI format for a UE depends on transmission mode (TM) setfor the UE. In other words, only a DCI format corresponding to aspecific TM can be used for a UE configured in the specific TM.

A PDCCH is transmitted on an aggregation of one or several consecutivecontrol channel elements (CCEs). The CCE is a logical allocation unitused to provide the PDCCH with a coding rate based on a state of a radiochannel. The CCE corresponds to a plurality of resource element groups(REGs). For example, a CCE corresponds to 9 REGs and an REG correspondsto 4 REs. 3GPP LTE defines a CCE set in which a PDCCH can be located foreach UE. A CCE set from which a UE can detect a PDCCH thereof is calleda PDCCH search space, simply, search space. An individual resourcethrough which the PDCCH can be transmitted within the search space iscalled a PDCCH candidate. A set of PDCCH candidates to be monitored bythe UE is defined as the search space. In 3GPP LTE/LTE-A, search spacesfor DCI formats may have different sizes and include a dedicated searchspace and a common search space. The dedicated search space is aUE-specific search space and is configured for each UE. The commonsearch space is configured for a plurality of UEs. Aggregation levelsdefining the search space is as follows.

TABLE3 Search Space Number of Aggregation Level PDCCH candidates Type LSize [in CCEs] M^((L)) UE-specific 1 6 6 2 12 6 4 8 2 8 16 2 Common 4 164 8 16 2

A PDCCH candidate corresponds to 1, 2, 4 or 8 CCEs according to CCEaggregation level. An eNB transmits a PDCCH (DCI) on an arbitrary PDCCHcandidate with in a search space and a UE monitors the search space todetect the PDCCH (DCI). Here, monitoring refers to attempting to decodeeach PDCCH in the corresponding search space according to all monitoredDCI formats. The UE can detect the PDCCH thereof by monitoring pluralPDCCHs. Since the UE does not know the position in which the PDCCHthereof is transmitted, the UE attempts to decode all PDCCHs of thecorresponding DCI format for each subframe until a PDCCH having the IDthereof is detected. This process is called blind detection (or blinddecoding (BD)).

The eNB can transmit data for a UE or a UE group through the dataregion. Data transmitted through the data region may be called userdata. For transmission of the user data, a physical downlink sharedchannel (PDSCH) may be allocated to the data region. A paging channel(PCH) and downlink-shared channel (DL-SCH) are transmitted through thePDSCH. The UE can read data transmitted through the PDSCH by decodingcontrol information transmitted through a PDCCH. Informationrepresenting a UE or a UE group to which data on the PDSCH istransmitted, how the UE or UE group receives and decodes the PDSCH data,etc. is included in the PDCCH and transmitted. For example, if aspecific PDCCH is CRC (cyclic redundancy check)-masked having radionetwork temporary identify (RNTI) of “A” and information about datatransmitted using a radio resource (e.g., frequency position) of “B” andtransmission format information (e.g., transport block size, modulationscheme, coding information, etc.) of “C” is transmitted through aspecific DL subframe, the UE monitors PDCCHs using RNTI information anda UE having the RNTI of “A” detects a PDCCH and receives a PDSCHindicated by “B” and “C” using information about the PDCCH.

A reference signal (RS) to be compared with a data signal is necessaryfor the UE to demodulate a signal received from the eNB. A referencesignal refers to a predetermined signal having a specific waveform,which is transmitted from the eNB to the UE or from the UE to the eNBand known to both the eNB and UE. The reference signal is also called apilot. Reference signals are categorized into a cell-specific RS sharedby all UEs in a cell and a modulation RS (DM RS) dedicated for aspecific UE. A DM RS transmitted by the eNB for demodulation of downlinkdata for a specific UE is called a UE-specific RS. Both or one of DM RSand CRS may be transmitted on downlink. When only the DM RS istransmitted without CRS, an RS for channel measurement needs to beadditionally provided because the DM RS transmitted using the sameprecoder as used for data can be used for demodulation only. Forexample, in 3GPP LTE(-A), CSI-RS corresponding to an additional RS formeasurement is transmitted to the UE such that the UE can measurechannel state information. CSI-RS is transmitted in each transmissionperiod corresponding to a plurality of subframes based on the fact thatchannel state variation with time is not large, unlike CRS transmittedper subframe.

FIG. 4 illustrates an exemplary uplink subframe structure used in 3GPPLTE/LTE-A.

Referring to FIG. 4, a UL subframe can be divided into a control regionand a data region in the frequency domain. One or more PUCCHs (physicaluplink control channels) can be allocated to the control region to carryuplink control information (UCI). One or more PUSCHs (Physical uplinkshared channels) may be allocated to the data region of the UL subframeto carry user data.

In the UL subframe, subcarriers spaced apart from a DC subcarrier areused as the control region. In other words, subcarriers corresponding toboth ends of a UL transmission bandwidth are assigned to UCItransmission. The DC subcarrier is a component remaining unused forsignal transmission and is mapped to the carrier frequency f0 duringfrequency up-conversion. A PUCCH for a UE is allocated to an RB pairbelonging to resources operating at a carrier frequency and RBsbelonging to the RB pair occupy different subcarriers in two slots.Assignment of the PUCCH in this manner is represented as frequencyhopping of an RB pair allocated to the PUCCH at a slot boundary. Whenfrequency hopping is not applied, the RB pair occupies the samesubcarrier.

The PUCCH can be used to transmit the following control information.

-   -   Scheduling Request (SR): This is information used to request a        UL-SCH resource and is transmitted using On-Off Keying (OOK)        scheme.    -   HARQ ACK/NACK: This is a response signal to a downlink data        packet on a PDSCH and indicates whether the downlink data packet        has been successfully received. A 1-bit ACK/NACK signal is        transmitted as a response to a single downlink codeword and a        2-bit ACK/NACK signal is transmitted as a response to two        downlink codewords. HARQ-ACK responses include positive ACK        (ACK), negative ACK (NACK), discontinuous transmission (DTX) and        NACK/DTX. Here, the term HARQ-ACK is used interchangeably with        the term HARQ ACK/NACK and ACK/NACK.    -   Channel State Indicator (CSI): This is feedback information        about a downlink channel. Feedback information regarding MIMO        includes a rank indicator (RI) and a precoding matrix indicator        (PMI).

The quantity of control information (UCI) that a UE can transmit througha subframe depends on the number of SC-FDMA symbols available forcontrol information transmission. The SC-FDMA symbols available forcontrol information transmission correspond to SC-FDMA symbols otherthan SC-FDMA symbols of the subframe, which are used for referencesignal transmission. In the case of a subframe in which a soundingreference signal (SRS) is configured, the last SC-FDMA symbol of thesubframe is excluded from the SC-FDMA symbols available for controlinformation transmission. A reference signal is used to detect coherenceof the PUCCH. The PUCCH supports various formats according toinformation transmitted thereon.

Table 4 shows the mapping relationship between PUCCH formats and UCI inLTE/LTE-A.

TABLE 4 Number of bits per PUCCH Modulation subframe, format schemeM_(bit) Usage Etc. 1 N/A N/A SR (Scheduling Request)  1a BPSK 1 ACK/NACKor One codeword SR + ACK/NACK  1b QPSK 2 ACK/NACK or Two codeword SR +ACK/NACK 2 QPSK 20 CQI/PMI/RI Joint coding ACK/NACK (extended CP)  2aQPSK + 21 CQI/PMI/RI + Normal CP BPSK ACK/NACK only  2b QPSK + 22CQI/PMI/RI + Normal CP QPSK ACK/NACK only 3 QPSK 48 ACK/NACK or SR +ACK/NACK or CQI/PMI/RI + ACK/NACK

Referring to Table 4, PUCCH formats 1/1a/1b are used to transmitACK/NACK information, PUCCH format 2/2a/2b are used to carry CSI such asCQI/PMI/RI and PUCCH format 3 is used to transmit ACK/NACK information.

Reference Signal (RS)

When a packet is transmitted in a wireless communication system, signaldistortion may occur during transmission since the packet is transmittedthrough a radio channel. To correctly receive a distorted signal at areceiver, the distorted signal needs to be corrected using channelinformation. To detect channel information, a signal known to both atransmitter and the receiver is transmitted and channel information isdetected with a degree of distortion of the signal when the signal isreceived through a channel. This signal is called a pilot signal or areference signal.

When data is transmitted/received using multiple antennas, the receivercan receive a correct signal only when the receiver is aware of achannel state between each transmit antenna and each receive antenna.Accordingly, a reference signal needs to be provided per transmitantenna, more specifically, per antenna port.

Reference signals can be classified into an uplink reference signal anda downlink reference signal. In LTE, the uplink reference signalincludes:

i) a demodulation reference signal (DMRS) for channel estimation forcoherent demodulation of information transmitted through a PUSCH and aPUCCH; and

ii) a sounding reference signal (SRS) used for an eNB to measure uplinkchannel quality at a frequency of a different network.

The downlink reference signal includes:

i) a cell-specific reference signal (CRS) shared by all UEs in a cell;

ii) a UE-specific reference signal for a specific UE only;

iii) a DMRS transmitted for coherent demodulation when a PDSCH istransmitted;

iv) a channel state information reference signal (CSI-RS) for deliveringchannel state information (CSI) when a downlink DMRS is transmitted;

v) a multimedia broadcast single frequency network (MBSFN) referencesignal transmitted for coherent demodulation of a signal transmitted inMBSFN mode; and

vi) a positioning reference signal used to estimate geographic positioninformation of a UE.

Reference signals can be classified into a reference signal for channelinformation acquisition and a reference signal for data demodulation.The former needs to be transmitted in a wide band as it is used for a UEto acquire channel information on downlink transmission and received bya UE even if the UE does not receive downlink data in a specificsubframe. This reference signal is used even in a handover situation.The latter is transmitted along with a corresponding resource by an eNBwhen the eNB transmits a downlink signal and is used for a UE todemodulate data through channel measurement. This reference signal needsto be transmitted in a region in which data is transmitted.

In FD-MIMO of LTE and MIMO of New RAT, discussion on an aperiodic CSI-RS(A-CSIRS) is in progress. The A-CSIRS corresponds to a CSI-RStransmitted at specific timing (e.g., a subframe, a slot, etc.). TheA-CSIRS informs a UE of the timing at which the A-CSIRS is transmittedvia DCI to make the UE use a corresponding RS for measuring CSI. Inparticular, when the A-CSIRS is transmitted, it is necessary to considera method of transmitting a data symbol which is transmitted attime/position at which a corresponding RS is transmitted.

A scheme used in LTE corresponds to a scheme of using rate-matching(RM). In particular, when rate matching is performed on a data symbol inan A-CSIRS RE, operations of a base station (BS) and a user equipment(UE) are described in the following. When the BS performs mapping on anRE of PDSCH, the BS sets a zero-power (ZP) CSI-RS (ZP-CSI-RS) includingan RE pattern of an RS transmitting an A-CSIRS to the UE. The BSperforms RE mapping under the assumption that PDSCH is not transmittedin a ZP-CSI-RS RE and may be then able to transmit PDSCH. And, the BStransmits A-CSIRS to an A-CSIRS RE. The UE performs decoding on thePDSCH by assuming the transmission operation of the BS. In particular,the UE performs decoding under the assumption that PDSCH is not mappedto a PDSCH muting RE to which a ZP-CSI-RS is set from the beginning.

A semi-persistent (SP) CSI-RS (SP-CSI-RS) is also considered in theFD-MIMO of LTE and the MIMO of New RAT. Similar to the A-CSIRS, theSP-CSIRS uses a method of transmitting a CSI-RS in a prescribed timeperiod via enable/disable signaling and has a characteristic thatwhether or not a CSI-RS is transmitted varies according to timing.

In order to use the scheme above, it is necessary for a base station anda UE to have signaling and configuration for using rate matching. Inparticular, since it is able to dynamically transmit the A-CSIRS inevery subframe, it is necessary to have dynamic signaling (e.g.,signaling such as DCI via PDCCH) corresponding to the A-CSIRS and aZP-CSI-RS configuration via higher layer signaling for the A-CSIRS. Inthe following, ‘rate matching’ can be simply referred to as ‘RM’. And, aZP CSI-RS or an NZP CSI-RS may corresponds to a resource in which‘CSI-RS’ is transmitted or may correspond to both a CSI-RS and aresource in which the CSI-RS is transmitted.

ZP-CSI-RS Configuration Method for Rate-Matching

For the aforementioned rate matching signaling, it may be able to definea configuration described in the following and the configuration can beset to a base station and a user equipment.

1. Configuration of ‘Rate Matching Setting’

Option 1: A rate matching setting corresponds to a set of the ‘L numberof links’ designating a ZP-CSI-RS (or a resource group) to be used forperforming rate matching in a ‘resource setting’ shared with ameasurement setting for CSI acquisition and/or beam management framework. FIG. 5 illustrates a rate matching setting having a sharingresource setting with a ZP-CSI-RS resource.

-   -   In FIG. 5, each link corresponds to a ZP-CSI-RS resource group.        In particular, a plurality of resource settings can be set to        each link as a rate matching pattern (refer to link 2 of the        ‘rate matching setting’ of FIG. 5). In this case, an actually        applied ZP-CSI-RS RE pattern corresponds to a union of a        plurality of configured ZP-CSI-RS resource RE patterns.    -   A resource setting corresponds to a set of RS RE pattern        candidates for ZP-CSI-RS. Each resource setting can include a        different type of an RS (e.g., DMRS, SRS, etc.). For the        resource setting, it may reuse an RS RE pattern for NZP-CSI-RS        defined for the CSI acquisition and/or beam management        framework. In this case, although the NZP-CSI-RS is used, if a        resource is linked in the rate matching setting, a base station        and a UE automatically interpret the resource as a ZP-CSI-RS.

Option 2: A rate matching setting corresponds to a set of the ‘L numberof links’ designating a ZP-CSI-RS (or a resource group) to be used forperforming rate matching in a ‘resource setting’ configured irrespectiveof a measurement setting for CSI acquisition and/or beam managementframe work. FIG. 6 illustrates a rate matching setting having a resourcesetting independent of a ZP-CSI-RS resource configuration.

-   -   In FIG. 6, each link corresponds to a ZP-CSI-RS resource group.        In particular, a plurality of resource settings can be set to        each link as a rate matching pattern (refer to link 2 of the        ‘rate matching setting’ of FIG. 6). In this case, an actually        applied ZP-CSI-RS RE pattern corresponds to a union of a        plurality of configured ZP-CSI-RS resource RE patterns.    -   A resource setting corresponds to a set of RS RE pattern        candidates for ZP-CSI-RS. Each resource setting can include a        different type of an RS (e.g., DMRS, SRS, etc.). The resource        setting includes the M (M>=1) number of candidate ZP-CSI-RS        patterns.

In particular, for clarity of configuration and signaling (e.g., inorder to reduce overhead), it may be able to define a ZP-CSI-RS patternfor performing RM using a part of available CSI-RE RE pattern candidatesonly. In particular, a resource setting for rate matching can includeall or a part of available CSI-RE RE patterns. For example, a ZP-CSI-RSRE pattern can include a pattern assuming the specific number of antennaports (e.g., 4 ports) only among CSI-RS patterns.

The resource setting can be forwarded to the UE via higher layersignaling such as RRC.

Other Configurations

-   -   A frequency granularity configuration (i.e., wideband/partial        band/subband) can be included in each link. In the present        specification, the frequency granularity corresponds to a unit        of frequency allocation. For example, if the frequency        granularity is configured by a wideband, frequency allocation        corresponds to the x number of resource blocks. If the frequency        granularity is configured by a partial band, frequency        allocation corresponds to the y number of resource blocks. If        the frequency granularity is configured by a subband, frequency        allocation may correspond to the z number of resource blocks. In        this case, x>y>z and the x, the y and the z correspond to        integers. In general, the frequency granularity may correspond        to a unit of frequency allocation for a single UE in a serving        cell. A data, a signal, and the like can be transmitted by a        base station or a serving cell within the aforementioned number        of resource blocks. Moreover, the frequency granularity can be        comprehended as a unit of frequency allocation different from        the aforementioned frequency allocation or a unit of frequency        domain.

In particular, it may be able to configure a resource having a pluralityof frequency configurations different from each other. For example, itmay be able to configure a wideband ZP-CSI-RS resource and a partialband ZP-CSI-RS resource.

If an additional frequency granularity-related configuration is notprovided, a base station and a UE follow a frequency granularityincluded in a designated ZP-CSI-RS RE pattern. If a frequencygranularity is not included in the ZP-CSI-RS RE pattern, the UE canperform data transmission and reception under the assumption that ratematching is performed on all scheduled bands.

-   -   A time configuration (i.e., aperiodic/semi-periodic/periodic)        can be included in each link.

More specifically, an aperiodic/semi-periodic/periodic ZP-CSI-RS can becomprehended as follows.

-   -   Aperiodic ZP-CSI-RS: an aperiodic ZP-CSI-RS is indicated to a UE        via L1 signaling such as DCI. Rate matching can be performed on        a corresponding resource pattern in a slot to which the L1        signaling is transmitted or a specific slot(s) designated by the        L1 signaling only.

In this case, aperiodic ZP-CSI-RS signaling via DCI can designates asemi-persistent ZP-CSI-RS resource or a periodic ZP-CSI-RS resource(i.e., a configuration or a setting to which a period/offset is set). Inthis case, it may ignore a configured period/offset.

-   -   Semi-persistent ZP CSI-RS: A semi-persistent ZP CSI-RS        enables/disables a rate matching operation on a resource(s)        designated via L1 and/or L2 signaling among ZP CSI-RS        resource(s) designated via L2 and/or L3 signaling. In this case,        it may perform rate matching on a corresponding resource with a        designated period/offset during the rate matching operation is        enabled.    -   Periodic ZP-CSI-RS: A periodic ZP-CSI-RS is similar to the        semi-persistent ZP-CSI-RS. However, separate enable/disable        signaling does not exist in the periodic ZP-CSI-RS. The periodic        ZP-CSI-RS operates as if a rate matching operation is always        enabled.

In particular, it may be able to configure a resource having a pluralityof time configurations different from each other. For example, it may beable to configure an aperiodic ZP-CSI-RS resource and a semi-persistentZP-CSI-RS resource.

2. Case that Rate Matching Setting is Included in Measurement Setting

A ZP-CSI-RS link is configured under a framework of a measurementsetting for CSI acquisition and/or beam management framework.

A resource setting corresponds to a set of RS RE pattern candidates forthe entire CSI-RSs (NZP and/or ZP CSI-RS). A different type of RSpattern (e.g., DMRS, SRS, etc.) can be included in the resource setting.When a link is configured for a ZP-CSI-RS, it may reuse an RS RE patternfor an NZP-CSI-RS, which is defined for CSI acquisition and/or beammanagement frame work. In this case, although the NZP-CSI-RS is used, ifa resource is linked in the rate matching setting, a base station and aUE can automatically interpret the resource as a ZP-CSI-RS. FIG. 7illustrates a ZP-CSI-RS configuration for performing rate matchingincluded in a measurement setting.

Similar to a link 4 or a link 5 of FIG. 7, if a reporting setting is notlinked with a specific resource setting or a separately configured ‘ratematching setting’ rather than the reporting setting is linked with thespecific resource setting in a measurement setting, a CSI-RS resource(or resource group) designated by the link can be comprehended as aZP-CSI-RS pattern dedicated for rate matching. In this case, a link forperforming rate matching can share an index of the link with a link forperforming CSI measurement/beam management within the measurementsetting.

3. Case that Rate Matching Setting is Included in Measurement SettingHaving Individual Resource Setting

Although the present case is similar to the aforementioned case that arate matching setting is included in a measurement setting, according tothe present case, it is able to configure a separate resource settingfor a ZP CSI-RS for performing rate matching.

In this case, the entire PDSCH region as well as a set of RSs may becomea target.

4. Case that Rate Matching Setting is Included in Resource Setting

-   -   1-bit indicator is allocated according to a resource (set)        included in a resource setting to configure whether or not the        resource setting is used for rate matching. FIG. 8 illustrates        an example of allocating a rate matching setting (i.e., an        indicator indicating whether or not a resource setting is used        for rate matching) to a resource setting.    -   A UE assumes that rate matching is performed on all resources        (or resource set) of which 1-bit indicator set to a resource        setting is configured by ‘RM on’.    -   The indicator can be commonly set to a ZP-CSI-RS and an NZP        CSI-RS. Both the ZP-CSI-RS and the NZP CSI-RS can be used as a        rate matching pattern.    -   In order to avoid transmitting data to an RE in which NZP-CSI-RS        is transmitted, the indicator can be configured to be used for        ZP-CSI-RS only. A UE or a base station can be configured to        perform rate matching on the NZP-CSI-RS by default. In        particular, the NZP-CSI-RS on which the rate matching is        performed by default can be restricted to an NZP-CSI-RS resource        included in a link configured to perform beam management/CSI        acquisition among NZP-CSI RS resources.

More specifically, a UE or a base station can perform rate matching onboth an NZP CSI-RS configured to measure a channel and an NZP CSI-RSconfigured to measure interference by default.

For the flexibility of interference measurement, when an NZP CSI-RS isconfigured to measure interference, if there is no additionalsignaling/configuration, a UE or a base station may not perform ratematching.

In this case, a time/frequency-related configuration may follow acorresponding NZP-CSI RS configuration.

-   -   In order to use an NZP-CSI-RS for performing rate matching, it        may use a separate time/frequency configuration. In this case,        it may use a higher unit (e.g.,        aperiodic→semi-persistent→periodic, partial band→wideband). To        this end, it may use a separate indicator. For example, if 1-bit        indicator is included in an NZP-CSI-RS, the indicator can be        comprehended as a ‘cell-specific CSI-RS resource’. Since all UEs        belonging to a cell are able to use the indicator for the        purpose of channel measurement and the like, a UE may operate        under the assumption that NZP-CSI-RS is always transmitted to a        corresponding resource. In particular, if the indicator        indicates ‘on’, a corresponding resource can be comprehended as        a semi-persistent/periodic ZP-CSI-RS irrespective of a time        configuration for an NZP-CSI-RS. A UE or a base station can        perform rate matching on the NZP-CSI-RS.

Method of Signaling Rate Matching

L1/L2 Indication for ZP-CSI-RS

1. ‘Rate Matching Setting’ Case (Related to FIG. 5)

-   -   A rate matching setting including a plurality of links can be        set to a UE via higher layer signaling such as RRC. A set of        ZP-CSI-RS patterns to be used is included in each of a plurality        of the links. A separate resource setting can be configured via        higher layer signaling such as RRC.    -   In order to have flexibility as much as about dozens ms, it is        able to define a ZP-CSI-RS link (group) to be actually used, via        MAC signaling. This scheme is comprehended as being identical to        a semi-persistent ZP-CSI-RS configuration. A semi-persistent        ZP-CSI-RS performs rate matching on a ZP-CSI-RS RE pattern        corresponding to links indicated from a subframe in which enable        signaling including an actually used ZP-CSI RS link (group) is        received to a subframe in which disable signaling is received.    -   For the flexibility of a subframe (or slot) unit, a ZP-CSI-RS        link (group) to be used as dynamic signaling can be set to a UE        via L1 signaling such as DCI. This can be performed in a manner        of designating a link to be actually used from among a link        group (or a link group sorted via MAC signaling) included in a        defined rate matching setting.

In case of an aperiodic ZP-CSI-RS, it may indicate that rate matching isperformed on a ZP-CSI-RS RE pattern corresponding to an indicated linkin a subframe in which DCI is transmitted.

In case of a semi-persistent ZP-CSI-RS, signaling transmitted via DCI iscomprehended as enable/disable signaling. It indicates that ratematching is performed on a ZP-CSI-RS RE pattern corresponding to linksindicated from a subframe in which enable signaling is received via DCIto a subframe immediately before a subframe in which disable signalingis received.

2. ‘Measurement Setting’ Case (Related to FIG. 7)

-   -   A ‘measurement setting’ including a ZP-CSI-RS link can be set to        a UE via higher layer signaling such as RRC.    -   For the flexibility as much as dozens ms, it is able to define a        ZP-CSI-RS link (group) to be actually used via MAC signaling.        The link can be selected using a scheme identical to a scheme of        selecting a link to be actually used for CSI measurement/beam        management from a measurement setting.

In this case, the ZP-CSI-RS link (group) can include a link formeasuring CSI (e.g., a link including a resource setting and a reportingsetting). In this case, the ZP-CSI-RS link is comprehended as aZP-CSI-RS link according to a resource setting which is designatedirrespective of a reporting setting. And, the scheme is comprehended asa scheme identical to a semi-persistent ZP-CSI-RS configuration. Thesemi-persistent ZP-CSI-RS indicates that rate matching is performed on aZP-CSI-RS RE pattern corresponding to links indicated from a subframeenable signaling is received to a subframe immediately before a subframein which disable signaling is received.

-   -   For the flexibility of a subframe (or slot) unit, a ZP-CSI-RS        link (group) to be used as dynamic signaling can be set to a UE        via L1 signaling such as DCI. This can be performed in a manner        of designating a link to be actually used from among a link        group (or a link group sorted via MAC signaling) included in a        defined rate matching setting.

In case of an aperiodic ZP-CSI-RS, it may indicate that rate matching isperformed on a ZP-CSI-RS RE pattern corresponding to an indicated linkin a subframe in which DCI is transmitted.

In case of a semi-persistent ZP-CSI-RS, signaling transmitted via DCI iscomprehended as enable/disable signaling. It indicates that ratematching is performed on a ZP-CSI-RS RE pattern corresponding to linksindicated from a subframe in which enable signaling is received via DCIto a subframe immediately before a subframe in which disable signalingis received.

3. ‘Resource Setting’ Case (Related to FIG. 8)

-   -   It may include the aforementioned 1-bit indicator in each        resource configuration included in a resource setting.    -   For the flexibility as much as dozens ms, it is able to include        L′-bit ZP-CSI-RS indicator via MAC signaling. Each bit of the        L′-bit ZP-CSI-RS indicator is matched with a resource        configuration (or a resource of which 1-bit indicator indicates        ‘rate matching on’ among the resource configuration) of the        resource setting by one-to-one. Information on whether or not        rate matching is performed on an RE pattern corresponding to a        resource can be signaled to a UE by toggling a bit by on/off.

The scheme above can be comprehended as a scheme identical to asemi-persistent ZP-CSI-RS configuration. The semi-persistent ZP-CSI-RSindicates that rate matching is performed on a ZP-CSI-RS RE patterncorresponding to links indicated from a subframe in which enablesignaling is received to a subframe immediately before a subframe inwhich disable signaling is received.

-   -   For the flexibility of a subframe (or slot) unit, it may be able        to transmit ‘ZP-CSI-RS indicator’ to a UE via L1 signaling such        as DCI. This means that it informs a UE of information on        whether or not rate matching is performed using an RE pattern        corresponding to a ZP-CSI-RS resource (group) configured via        higher layer signaling.

In case of an aperiodic ZP-CSI-RS, it may indicate that rate matching isperformed on a ZP-CSI-RS RE pattern corresponding to an indicatedresource (or a resource group) in a subframe in which DCI istransmitted.

In case of a semi-persistent ZP-CSI-RS, signaling transmitted via DCI iscomprehended as enable/disable signaling. It indicates that ratematching is performed on a ZP-CSI-RS RE pattern corresponding toresources (or a resource group) indicated from a subframe in whichenable signaling is received via DCI to a subframe immediately before asubframe in which disable signaling is received.

4. Other Configurations

-   -   Frequency-Related Configuration

For the flexibility of configuration, a frequency granularity can be setto a UE via L2 signaling such as MAC or L1 signaling such as DCI insteadof higher layer signaling.

In this case, the configured frequency granularity is identicallyapplied to the whole of a ZP-CSI-RS pattern. In particular, thefrequency granularity is configured by one of a partial band and awideband using 1-bit indicator.

In this case, the partial band may correspond to a band (or a band set)having a different numerology and/or a different operation scheme (e.g.,eMBB, eMTC) similar to an eMBB (enhanced mobile broadband) band.

Or, the partial band may correspond to a configured band group and theband group can be configured via separate signaling via higher layersignaling.

If a separate frequency granularity-related configuration is notprovided, a base station and a UE may follow a frequency granularityincluded in higher layer signaling. Or, in order to reduce signalingoverhead, the UE can perform data transmission and reception under theassumption that rate matching is performed on all scheduled bands,

-   -   Time-Related Configuration

For the flexibility of configuration, timing characteristic and/or aperiod/offset (semi-persistent or periodic) can be set to a UE via L2signaling such as MAC or L1 signaling such as DCI instead of higherlayer signaling.

Since the L1 signaling corresponds to signaling related toallocation/demodulation of PDSCH, it is preferable to transmit the L1signaling via DL-related UE-specific DCI together with a DL grant (DLscheduling).

In order to transmit matching signaling for the entire cell or aspecific UE group, it may use a sort of cell-specific DCI and/or UEgroup-specific DCI. In particular, it may be able to transmit the ratematching signaling by including the rate matching signaling in the DCI.FIG. 9 illustrates payload of the cell-specific DCI and/or the UEgroup-specific DCI.

In particular, it may have a structure that the certain numbers ofpayloads each of which has a specific length are adjacent to each other.A position of each payload (or a payload index) may have a meaningdescribed in the following.

1. UE

A position of a payload (or a payload index) may correspond toinformation for a specific UE.

-   -   In this case, contents transmitted to a payload may correspond        to signaling related to a UE operation configured in advance or        configured via RRC/MAC signaling. FIG. 10 illustrates DCI to        which a payload for each UE is set. For example, when a payload        1 is tied with a UE 1, signaling transmitted to a position of        the payload 1 can signal an operation (e.g., channel        measurement, interference measurement, etc.) to be performed in        the UE 1 and/or a target resource performing the operation. In        particular, if contents indicating ‘no RS’ are included in        signaled information, it may be able to inform a cell/UE group        that a corresponding UE does not designate a resource to be used        and there is no resource on which rate matching is to be        performed by a different UE. The signaling can specify a        cell-specific group or a UE-specific group.

In particular, an indication of a UE can be replaced with an indicationof a DMRS port and/or an indication of a sequence scrambling parameter(e.g., a specific parameter ID such as a virtual cell-ID, and the likeand/or a sequence seed ID such as nSCID and the like). For example,assume that a UE indicates using a DMRS port. In this case, an operationindicated in a payload 1 can indicate that the UE currently uses a DMRSport 7. To this end, it may be able to designate a separate payload fora UE to which a DMRS port is not allocated, i.e., a not scheduled UE.

In particular, a plurality of DMRS ports and/or a plurality of sequencescrambling parameters may use a single payload in consideration of thefrequency of using a DMRS port and/or a sequence scrambling parameter.In this case, a state of the payload can be jointly coded by combining aport (and/or a sequence scrambling parameter)(index) with an operationin a port (and/or a sequence scrambling parameter) group.

-   -   Or, each payload can indicate an operation to be performed by a        resource and a UE. FIG. 11 illustrates am example that a payload        indicates a resource and a UE operation in the resource. For        example, when there is a payload of N bits, the payload        indicates a resource to a UE using (N−1) bits and indicates an        operation (e.g., channel measurement, interference measurement,        etc.) to be performed in the indicated resource using the        remaining 1 bit. In this case, a UE set to the payload performs        a designated operation in a designated resource and the        remaining UEs can perform rate matching on all resources not        designated as ‘no RS’.    -   Or, each payload can designate a resource. FIG. 12 illustrates        an example that a payload for a UE indicates a resource. A UE        performs rate matching on all resources (i.e., a union of        resources designated by all payloads) not designated as ‘no RS’        In particular, the UE performs an operation designated by        signaling transmitted to a payload corresponding to the UE on a        corresponding resource. The operation for the signaling can be        configured via higher layer signaling in advance.

2. Resource

In this case, each position corresponds to a position of atime-frequency (code division multiplexed) resource configured inadvance or configured via RRC/MAC signaling. FIG. 13 illustrates anexample of DCI including a payload for each resource. In this case,signaling transmitted to each payload may correspond to a UE operationfor each resource and/or a UE performing the operation. For example,when a payload 1 is tied with a CSI-RS resource 1, signaling transmittedto a position of the payload 1 may correspond to signaling for anoperation (e.g., channel measurement, interference measurement, etc.) tobe performed in a configured resource 1. The signaling can specify acell-specific group or a UE-specific group.

Or, a payload can indicate an operation for a resource tied with thepayload and a UE performing the operation. FIG. 14 illustrates a payloadfor a resource including a UE indication and an operation for theindicated UE. For example, each payload consists of 2 bits and eachstate of the 2 bits includes ‘no measurement’, ‘channel measurement’,interference measurement’, and ‘channel and interference measurement’.In this case, a UE of each state and a higher layer configuration for anoperation are provided to each UE. In this case, each UE can performrate matching on all resources indicating a state rather than ‘nomeasurement’.

And, ‘rate matching only’ is added to signaled states to make UEsreceiving DCI perform rate matching only on a corresponding resourcewithout a separate operation.

UE signaling can be replaced with DMRS port signaling and/or a sequencescrambling parameter (e.g., a specific parameter ID such as a virtualcell ID and the like and/or a sequence seed ID such as nSCID and thelike). For example, when a UE is indicated by a DMRS port, it mayindicate ‘DMRS port 7’ instead of a UE index to indicate that anoperation indicated by a corresponding payload corresponds to anoperation for a UE currently using ‘DMRS port 7’. In this case, if astate indicated by a payload for a non-scheduled UE includes a stateindicating ‘non-scheduled UE’, it may be able to signal an operation fora UE to which a DMRS port is not provided.

3. Operation

Or, each payload can indicate an operation to be performed by a UE only.FIG. 15 illustrates DCI indicating an operation to be performed by a UEas a payload for a resource. For example, each payload consists of 2bits and each state includes ‘no measurement’, ‘channel measurement’,interference measurement’, and ‘channel and interference measurement’.When a payload 1 is configured to be tied with an aperiodic CSI-RSresource 1 and the aperiodic CSI-RS resource 1 is allocated to a UE 1and a UE 2 for channel measurement, if the payload 1 signals ‘channelmeasurement’, the UE 1 and the UE 2 perform a channel measurementoperation on the CSI-RS resource 1 at the same time. In this case, ahigher layer configuration for connecting an operation with a resourceis provided to each of the UEs.

And, ‘rate matching only’ is added to signaled states to make UEsreceiving DCI perform rate matching only on a corresponding resourcewithout a separate operation.

In particular, each payload can inform a UE oftransmission/non-transmission of an RS only. In other word, each payloadcan trigger a resource preset to a UE and an operation in the resource.For example, when a payload 1 is configured to be tied with an aperiodicCSI-RS resource 1, a UE 1 is configured to perform channel measurementon the aperiodic CSI-RS resource 1, and a UE 2 is configured to performinterference measurement on the aperiodic CSI-RS resource 1, ifsignaling indicating ‘measurement’ is transmitted to the payload 1, theUE 1 performs channel measurement in the resource and the UE 2 performsinterference measurement in the resource. In this case, a connectionbetween a resource and an operation in the resource can be indicated toa UE via higher layer signaling. FIG. 16 illustrates the payload.

4. No Meaning

A payload position (or index) has no meaning. A payload can include 3contents including resource indication, a target UE, and an operation.FIG. 17 illustrates the contents included in a payload. A UE performsrate matching on all resources. If a payload designating the UE exists,the UE performs an operation indicated by the payload in a resourceindicated by the payload. In this case, in order to reduce a DCI blinddecoding count of the UE, the number of payloads can be determined inadvance or can be designated to the UE via higher layer signaling suchas RRC and MAC signaling.

In this case, if the resource indication indicates ‘no RS’, the UE maynot read UE indication and an operation for UE. In this case, it mayconfigure and/or signal resource/UE/operation except RS configurationusing the aforementioned scheme. In this case, a UE can operateaccording to the configured resource/operation based on an RSadditionally set to the UE.

The aforementioned RM operation may correspond to an aperiodic RM and asemi-persistent RM (enable/disable). More specifically, in case of thesemi-persistent RM, if specific DCI is received, an RM operation ispersistently applied to each of instances according to a predeterminedperiod at the corresponding timing and thereafter (until differentdisable or updating DCI is received) using at least one of theaforementioned methods. RNTI (e.g., SI-RNTI or a separate UE-group-RNTI)for decoding DCI is provided to a UE in advance and the UE may attemptto perform blind decoding on cell-specific DCI or UE-group-specific DCIusing the RNTI. Or, semi-persistent RM can be set to a UE via MACsignaling and the RM operation can be restricted to an aperiodic RMonly.

UE operation-related signaling can be included in separate UE-specificDCI. In other word, if RM signaling is transmitted or received viacell-specific DCI/UE group-specific DCI, 1-bit signaling of the separateUE-specific DCI recognizes a resource designated by the cell-specificDCI/UE group-specific DCI as an aperiodic NZP CSI-RS resource and canindicate an operation of performing measurement or an operation of notperforming measurement. Moreover, the 1-bit signaling can be combined(jointly encoding) or integrated with aperiodic NZP CSI-RS indication.Similarly, it may designate an RM operation by setting a limit on a sizeof an aperiodic RM signaling field by 1 bit. And, it may be able toconfigure to perform RM on a resource designated by the cell-specificDCI/UE group-specific DCI. This operation has a meaning that signalingindicating an RM target resource and signaling indicating whether or notRM is actually performed are separated from each other usingcell-specific DCI/UE group-specific DCI and UE-specific DCI,respectively. If an RM target resource designated by the cell-specificDCI/UE group-specific DCI does not exist or is not received, a UE canperform aperiodic reporting on a resource designated for a differentreporting (e.g., periodic/semi-persistent reporting).

When multiple slots are scheduled using single DCI, RM designated by theDCI can be identically performed using a scheme designated for a slotscheduled by the DCI. In this case, it is able to indicate RM to themultiple slots without additional signaling overhead. On the contrary,it may perform RM on too many resources. In order to solve the problem,it may be able to designate slot timing at which RM is actuallyperformed via separate signaling. The DCI can designate a slot offset onthe basis of the timing at which the DCI is signaled. When RM isdesignated to multiple timings within a slot group scheduled by singleDCI, a base station can designate an RM slot pattern designated viahigher layer signaling such as RRC/MAC as DCI. The RM slot patterncorresponds to a set of slots performing RM within the slot groupscheduled by the single DCI. The RM slot pattern can be designated by abit map or a period and/or an offset for full flexibility. The RM slotcan be signaled in a manner of being combined with the RM signaling toreduce signaling overhead.

In case of a DMRS, it may consider applying a ZP CSI-RS for the RM to anadditional DMRS pattern. It may use an additional DMRS according to UEenvironment (e.g., Doppler spread according to a speed of a UE, etc.)irrespective of a DMRS pattern shared by all UEs. The additional DMRS isused in a manner of transmitting the additional DMRS to a legacy DMRS.RM for a DMRS pattern can be used to measure interference. And, whenmultiple users using a different additional DMRS pattern (e.g., a UEusing an additional DMRS and a UE not using the additional DMRS) arescheduled, the additional DMRS can be used for cancelling interferencein detecting a DMRS. In this case, when the ZP CSI-RS for the RM is usedfor a DMRS, the DMRS can be restricted to an additional DMRS to reducesignaling overhead.

In FDR (full duplex radio) case, UEs different from each other canperform DL reception/UL transmission in the same slot. In this case, inorder to protect an SRS transmitted by a UE performing UL transmission,it may perform RM on an SRS position. The SRS can be transmitted byconcentrating power on a partial band for channel measurementperformance. In order to perform channel measurement on the whole band(or a configured band) using the SRS transmission scheme, it mayconsider SRS hopping. It may additionally configure a hopping pattern ofan SRS on which RM is to be performed or a parameter determining thehopping pattern in consideration of the SRS hopping.

For an (NZP) CSI-RS enabled/disabled by RRC/MAC signaling, in order tomute transmission/measurement of the CSI-RS at the specific timing, itmay transmit CSI-RS muting signaling. In particular, similar to RMperformed on PDSCH, a UE does not measure an NZP CSI-RS for a signaledresource (time/frequency) to provide additional flexibility toperiodic/semi-persistent NZP CSI-RS via the MAC/RRC configuration and/orIMR (interference measurement resource) via DCI. In particular, when NZPCSI-RS resources are configured in a manner of being overlapped, aplurality of UEs are able to share the resources using theabovementioned method. And, a UE measures a channel of the UE from aCSI-RS resource, exclude the channel from the resource, and uses theremaining channels as interference using the method. In other word, whena resource for measuring a channel and an IMR are configured in a mannerof being overlapped, a base station can transmit a differentinterference hypothesis to a UE at the timing at which CSI-RS/IMR istransmitted using the method.

To this end, it may provide RM signaling corresponding to the overlappedNZP CSI-RS resource position. In this case, although a legacy RMsignaling means that a PDSCH symbol is not transmitted in an NZP CSI-RSresource, if the RM signaling indicates or configures a part of theoverlapped NZP CSI-RS, it means that a UE does not measure the NZP CSIRSresource. To this end, it may generate a field for RM signalingindicating an NZP CSI-RS resource in DCI.

Or, it may be able to configure a ZP CSI-RS using one of states ofaperiodic CSI-RS indication to reduce signaling overhead. In particular,an aperiodic NZP CSI-RS, a periodic/semi-persistent NZP CSI-RS, aZP-CSI-RS having the same resource, or a resource configurationindicating that a corresponding resource is not measured can be set toone of the states of the aperiodic CSI-RS indication. Hence, if a UEreceives the aperiodic CSI-RS indication state, the UE does not use aCMR (channel measurement resource)/IMR transmitted from a correspondingslot for periodically measured and reported CSI. In addition, the UE maynot report the CSI or may report non-updated CSI.

Or, if the UE receives aperiodic CSI-RS indication, the UE can beconfigured not to perform measurement on a different CMR/IMR transmittedfrom a corresponding slot or a CMR/IMR to which a higher layerconfiguration is transmitted in advance.

In particular, it may perform RM on a part of the NZP CSI-RS only. Thisis because it is not necessary for transmission of the NZP CSI-RS tohave high density to measure interference only and it is necessary toenhance channel estimation performance of a UE performing channelestimation in a collision resource.

Moreover, in the description mentioned earlier in FIGS. 5 to 8, if asingle reporting setting is restricted to be tied with a single link, itis apparent that a scheme of indicating a reporting setting is identicalto the signaling scheme of the ‘link’. And, the aforementioned ZP CSI-RScorresponds to a resource for performing RM. As mentioned in theforegoing description, the resource may include a different type of anRS (or an RS resource) such as a DMRS in addition to a NZP CSI-RS and aZP CSI-RS. Hence, it may consider a different name (e.g., RM resource(RMR) instead of the ZP CSI-RS. In this case, it is apparent that theaforementioned operation is identically applied.

When ZP CSI-RS is signaled using DCI (i.e., aperiodic ZP CSI-RS) and theRM scheme is used, if it fails to receive DCI, it is unable to decodethe whole of a subframe. Hence, a UE and a base station can promise thatthe information is used not for RM bur for indicating an RE puncturingpattern of data not. In particular, when the base station maps an RE ofdata, the base station perform RE mapping under the assumption that datais transmitted in a ZP CSI-RS RE as well and does not transmit the datamapped in the RE at the final transmission timing. And, a UE performsdecoding on the data by assuming the transmission operation of the basestation. Consequently, the UE assumes that noise and a dummy value areincluded in a muting RE instead of data. When channel decoding isperformed in the muting RE, the UE does not perform LLR (log-likelihoodratio) calculation in the muting RE. Or, the UE can perform the LLRcalculation under the assumption that a data bit 0 and a data bit 1 havethe same probability. In this case, additional signaling is notnecessary in a system. Although a UE fails to receive DCI, the UE mayhave a transmission success probability of a certain level with the helpof channel coding.

In particular, when data is transmitted and received without receivingDCI (e.g., semi-persistent scheduling (SPS)), if blind decoding isperformed on DCI in every subframe for an RM operation using a ZP CSI-RS(i.e., aperiodic ZP CSI-RS), it is not preferable in terms of batteryconsumption of a UE. In particular, when data is transmitted andreceived using an SPS, RM signaling provided by DCI among the ZP CSI-RSpattern can be comprehended as a puncturing pattern instead of the RMpattern by a base station and a UE. For example, when SPS data istransmitted to a specific UE, if a base station intends to transmit datausing an aperiodic ZP CSI-RS by an aperiodic CSI-RS and the like, thebase statin performs data allocation under the assumption that a ZPCSI-RS RE pattern corresponds to an RE muting pattern for the UEreceiving the SPS data. In this case, the base station does not transmitadditional ZP CSI-RS indication-related DCI. In this case, a ZP CSI-RSconfigured via higher layer signaling such as RRC or MAC can perform anRM operation. In other word, a base station transmitting SPS data and aUE receiving the SPS data may operate under the assumption that RM isperformed on a predetermined periodic (and/or a semi-persistent) ZPCSI-RS in the middle of transmitting and receiving the SPS data and anaperiodic ZP CSI-RS is not indicated by the base station.

An RMR described in the present specification can be differentlyconfigured according to an (analog and/or digital) transmission beam ofa base station. For example, as shown in FIG. 18, when an RAMconfiguration is provided for a UE 2 using a beam 1 to transmit PDSCH,it is necessary to configure an RMR in the beam 1 to protect an NZPCSI-RS transmitted using a beam 3. However, it is not necessary to setthe RMR to the UE 1 that uses a beam 2 not affecting transmission of thebeam 3. If the UE 2 moves to a position of the UE 1 and uses the beam 2instead of the beam 1 to transmit PDSCH, it is not preferable to use thesame RMR for PDSCH RM of the UE 2. In legacy LTE environment, sinceswitching of a transmission (or reception) beam is semi-staticallyperformed, a ZP CSI-RS, which is configured via RRC configuration, issufficient for the switching. However, a legacy scheme may be notappropriate for New RAT considering a more dynamic beam change.

Hence, a plurality of RMRs are set to a UE in a manner of beingassociated with a transmission beam of a base station. If a specifictransmission beam is used to transmit PDSCH, the base station/UE can beconfigured to perform RM on an RMR associated with the transmission beamto transmit and receive data. A transmission beam can be associated withan RMR using methods described in the following.

1. RMR is Associated with Transmission Beam Index

-   -   If a transmission beam and a transmission beam index according        to the transmission beam are commonly defined/configured between        a base station and a UE, a transmission beam index is set to        each RMR. If a transmission beam having a specific index is used        to transmit PDSCH, it may be able to perform PDSCH RM using an        RMR corresponding to the transmission beam index. On the        contrary, it may be able to configure a different RMR according        to a transmission beam index. In this case, it may be able to        inform a UE of a beam index to be currently used via L1/L2        signaling.    -   Similarly, if a link of a pair of beams of a transmission beam        and a reception beam is defined, a transmission beam index can        be replaced with an index of the link of the pair of beams.

2. RMR is Associated with CRI (CSI-RS Resource Indicator)

-   -   If a transmission beam is associated with an NZP CSI-RS via a        parameter such as QCL (quasi-co-located), a transmission beam of        the “1. Association with transmission beam index” case can be        replaced with the NZP CSI-RS. In particular, not a ‘transmission        beam’ but an NZP CSI-RS is associated with each RMR. The NZP        CSI-RS corresponds to an RS to which a transmission beam is        reflected in beam management and the like. In particular, the        NZP CSI-RS can be used in a manner of being associated with a        CRI reported in the beam management stage. The method above can        more UE-transparently operate compared to a method of explicitly        associating with a transmission beam.    -   In case of using a QCL parameter, the QCL parameter can be        restricted to a spatial QCL part (i.e., an arrival angle and/or        angle spread).

In the methods above, it is not necessary to map a transmission beam (ora parameter corresponding to the beam) and an RMR by one-to-one. Inparticular, one RMR can be associated with beams different from eachother at the same time and one transmission beam can be associated witha plurality of RMRs. And, instead of a transmission beam, a transmissionbeam group (e.g., cell-center beam group/cell-edge beam group) for anRMR can be defined. In particular, an RMR can be configured according toa transmission beam group for the RMR. The abovementioned configurationcan be included in a resource setting of an RMR. In an RM setting and/ora measurement setting, it may be able to define links different fromeach other (i.e., a plurality of RMR groups) according to a beam indexor a parameter related to the beam index in consideration of additionalMAC/DCI signaling. And, association between a transmission beam and anRMR can be included in RRC/MAC signaling.

If multiple transmission beams are used for transmitting data in a slot,a UE may apply a different RMR in a unit (e.g., symbol) of changing atransmission beam in the slot. In other word, if a transmission beam fortransmitting data is changed in every 7 symbols in a slot, an RMRpattern used in the first 7 symbols may be different from an RMR patternused in the second 7 symbols. Or, in order to reduce complexity, an RMRcorresponding to a union of all RMRs corresponding to multipletransmission beams for transmitting data can be used as an RMR of acorresponding slot.

According to the method above, since additional dynamic signaling is notused, the method can be usefully utilized for such a configuration as aperiodic/semi-persistent RMR having latency longer than DCI. Inaperiodic/semi-persistent RMR, an RMR candidate capable of beingdesignated via signaling can be determined according to a transmissionbeam (or transmission beam group). In this case, transmissionbeam-related information can be included in signaling of the RMRcandidate. If the number of RMR candidates is considerably less, amethod of associating the RMR candidate with a transmission beam isomitted. Instead, a base station may select/transmit an appropriate RMRvia MAC and/or DCI signaling.

FIG. 9 is a block diagram illustrating a transmitting device 10 and areceiving device 20 configured to implement embodiments of the presentinvention. Each of the transmitting device 10 and receiving device 20includes a transmitter/receiver 13, 23 capable of transmitting orreceiving a radio signal that carries information and/or data, a signal,a message, etc., a memory 12, 22 configured to store various kinds ofinformation related to communication with a wireless communicationsystem, and a processor 11, 21 operatively connected to elements such asthe transmitter/receiver 13, 23 and the memory 12, 22 to control thememory 12, 22 and/or the transmitter/receiver 13, 23 to allow the deviceto implement at least one of the embodiments of the present inventiondescribed above.

The memory 12, 22 may store a program for processing and controlling theprocessor 11, 21, and temporarily store input/output information. Thememory 12, 22 may also be utilized as a buffer. The processor 11, 21controls overall operations of various modules in the transmittingdevice or the receiving device. Particularly, the processor 11, 21 mayperform various control functions for implementation of the presentinvention. The processors 11 and 21 may be referred to as controllers,microcontrollers, microprocessors, microcomputers, or the like. Theprocessors 11 and 21 may be achieved by hardware, firmware, software, ora combination thereof. In a hardware configuration for an embodiment ofthe present invention, the processor 11, 21 may be provided withapplication specific integrated circuits (ASICs) or digital signalprocessors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), and field programmable gate arrays(FPGAs) that are configured to implement the present invention. In thecase which the present invention is implemented using firmware orsoftware, the firmware or software may be provided with a module, aprocedure, a function, or the like which performs the functions oroperations of the present invention. The firmware or software configuredto implement the present invention may be provided in the processor 11,21 or stored in the memory 12, 22 to be driven by the processor 11, 21.

The processor 11 of the transmitter 10 performs predetermined coding andmodulation of a signal and/or data scheduled by the processor 11 or ascheduler connected to the processor 11, and then transmits a signaland/or data to the transmitter/receiver 13. For example, the processor11 converts a data sequence to be transmitted into K layers throughdemultiplexing and channel coding, scrambling, and modulation. The codeddata sequence is referred to as a codeword, and is equivalent to atransport block which is a data block provided by the MAC layer. Onetransport block is coded as one codeword, and each codeword istransmitted to the receiving device in the form of one or more layers.To perform frequency-up transformation, the transmitter/receiver 13 mayinclude an oscillator. The transmitter/receiver 13 may include Nttransmit antennas (wherein Nt is a positive integer greater than orequal to 1).

The signal processing procedure in the receiving device 20 is configuredas a reverse procedure of the signal processing procedure in thetransmitting device 10. The transmitter/receiver 23 of the receivingdevice 20 receives a radio signal transmitted from the transmittingdevice 10 under control of the processor 21. The transmitter/receiver 23may include Nr receive antennas, and retrieves baseband signals byfrequency down-converting the signals received through the receiveantennas. The transmitter/receiver 23 may include an oscillator toperform frequency down-converting. The processor 21 may perform decodingand demodulation on the radio signal received through the receiveantennas, thereby retrieving data that the transmitting device 10 hasoriginally intended to transmit.

The transmitter/receiver 13, 23 includes one or more antennas. Accordingto an embodiment of the present invention, the antennas function totransmit signals processed by the transmitter/receiver 13, 23 are toreceive radio signals and deliver the same to the transmitter/receiver13, 23. The antennas are also called antenna ports. Each antenna maycorrespond to one physical antenna or be configured by a combination oftwo or more physical antenna elements. A signal transmitted through eachantenna cannot be decomposed by the receiving device 20 anymore. Areference signal (RS) transmitted in accordance with a correspondingantenna defines an antenna from the perspective of the receiving device20, enables the receiving device 20 to perform channel estimation on theantenna irrespective of whether the channel is a single radio channelfrom one physical antenna or a composite channel from a plurality ofphysical antenna elements including the antenna. That is, an antenna isdefined such that a channel for delivering a symbol on the antenna isderived from a channel for delivering another symbol on the sameantenna. An transmitter/receiver supporting the Multiple-InputMultiple-Output (MIMO) for transmitting and receiving data using aplurality of antennas may be connected to two or more antennas.

In embodiments of the present invention, the UE or the terminal operatesas the transmitting device 10 on uplink, and operates as the receivingdevice 20 on downlink. In embodiments of the present invention, the eNBor the base station operates as the receiving device 20 on uplink, andoperates as the transmitting device 10 on downlink.

The transmitting device and/or receiving device may be implemented byone or more embodiments of the present invention among the embodimentsdescribed above.

As an embodiment, a terminal for decoding a downlink signal in awireless communication system is proposed. The terminal includes atransmitter, a receiver, and a processor that controls the transmitterand the receiver, the processor may receive a semi-persistent zeropower-channel state information reference signal (SP ZP CSI-RS) resourceconfiguration from a base station, decode a downlink signal according tothe SP ZP CSI-RS resource configuration. In this case, the SP ZP CSI-RSresource configuration may include a plurality of SP ZP CSI-RS resourcesand information on whether or not each of SP ZP CSI-RS resources is usedmay be indicated or configured by the base station.

Additionally or alternatively, the SP ZP CSI-RS resource configurationmay be independent of a resource configuration for performingmeasurement of the terminal.

Additionally or alternatively, the processor may perform rate matchingin an SP ZP CSI-RS resource enabled by a period and an offset indicatedby the SP ZP CSI-RS resource configuration according to the SP ZP CSI-RSresource configuration.

Additionally or alternatively, a signal for enabling or disabling the SPZP CSI-RS resource may include DCI (downlink control information) or MAC(medium access control) signaling.

Additionally or alternatively, each of the SP ZP CSI-RS resources mayhave a frequency configuration. And, the frequency configuration may beprovided by a separate signaling from the SP ZP CSI-RS resourceconfiguration.

Additionally or alternatively, each of the SP ZP CSI-RS resources isassociated with a respective one of transmission beams used by the basestation and an SP ZP CSI-RS resource associated with the transmissionbeam can be used for decoding the downlink signal.

Detailed descriptions of preferred embodiments of the present inventionhave been given to allow those skilled in the art to implement andpractice the present invention. Although descriptions have been given ofthe preferred embodiments of the present invention, it will be apparentto those skilled in the art that various modifications and variationscan be made in the present invention defined in the appended claims.Thus, the present invention is not intended to be limited to theembodiments described herein, but is intended to have the widest scopeconsistent with the principles and novel features disclosed herein.

INDUSTRIAL APPLICABILITY

The present invention can be used for such a wireless communicationdevice as a terminal, a relay, a base station, and the like.

What is claimed is:
 1. A method of decoding a downlink data by a terminal in a wireless communication system, the method comprising: receiving, from a base station, resource configuration information for configuring zero power-channel state information reference signal (ZP CSI-RS) resource sets for semi-persistent (SP) ZP CSI-RS, wherein each of the ZP CSI-RS resource sets includes a plurality of ZP CSI-RS resources, and the resource configuration information includes information about a periodicity and an offset for the SP ZP CSI-RS; receiving, from the base station, first information for enabling at least one ZP CSI-RS resource set for the SP ZP CSI-RS among the ZP CSI-RS resource sets; and receiving and decoding the downlink data based on the resource configuration information and the first information, wherein based on the enabling of the at least one ZP CSI-RS resource set, and based on the information about the periodicity and the offset for SP ZP CSI-RS, the downlink data is not mapped to the at least one ZP CSI-RS resource set, and wherein based on second information for disabling the at least one ZP CSI-RS resource set, the non-mapping of the downlink data to the at least one ZP CSI-RS resource set is ceased.
 2. The method of claim 1, wherein the resource configuration information is independent of a resource configuration for performing measurement of the terminal.
 3. The method of claim 1, wherein the first information is received via MAC (medium access control) signaling.
 4. The method of claim 1, wherein each of the ZP CSI-RS resource sets has a frequency configuration.
 5. The method of claim 4, wherein the frequency configuration is provided by a separate signaling from the resource configuration information.
 6. The method of claim 1, wherein each of the ZP CSI-RS resource sets is associated with a respective one of transmission beams used by the base station, and wherein a ZP CSI-RS resource set associated with a transmission beam used for the downlink data is used for decoding the downlink data.
 7. The method of claim 1, further comprising: performing rate matching for the decoding of the downlink data based on the first information.
 8. The method of claim 1, wherein decoding the downlink data based on the resource configuration information and the first information comprises: decoding the downlink data based on the at least one ZP CSI-RS resource set being enabled for the SP ZP CSI-RS so as not to be available for reception of the downlink data.
 9. A terminal configured to decode a downlink data in a wireless communication system, comprising: a transmitter and a receiver; at least one processor; and at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed by the at least one processor, perform operations comprising: receiving, from a base station through the receiver, resource configuration information for configuring zero power-channel state information reference signal (ZP CSI-RS) resource sets for semi-persistent (SP) ZP CSI-RS, wherein each of the ZP CSI-RS resource sets includes a plurality of ZP CSI-RS resources, and the resource configuration information includes information about a periodicity and an offset for the SP ZP CSI-RS; receiving, from the base station through the receiver, first information for enabling at least one ZP CSI-RS resource set for the SP ZP CSI-RS among the ZP CSI-RS resource sets; and receiving and decoding the downlink data based on the resource configuration information and the first information, wherein based on the enabling of the at least one ZP CSI-RS resource set, and based on the information about the periodicity and the offset for SP ZP CSI-RS, the downlink data is not mapped to the at least one ZP CSI-RS resource set, and wherein based on second information for disabling the at least one ZP CSI-RS resource set, the non-mapping of the downlink data to the at least one ZP CSI-RS resource set is ceased.
 10. The terminal of claim 9, wherein the resource configuration information is independent of a resource configuration for performing measurement of the terminal.
 11. The terminal of claim 9, wherein the first information is received via MAC (medium access control) signaling.
 12. The terminal of claim 9, wherein each of the ZP CSI-RS resource sets has a frequency configuration.
 13. The terminal of claim 12, wherein the frequency configuration is provided by a separate signaling from the resource configuration information.
 14. The terminal of claim 9, wherein each of the ZP CSI-RS resource sets is associated with a respective one of transmission beams used by the base station, and wherein a ZP CSI-RS resource set associated with a transmission beam used for the downlink data is used for decoding the downlink data.
 15. A method of transmitting a downlink data by a base station in a wireless communication system, the method comprising: transmitting, to a terminal, resource configuration information for configuring zero power-channel state information reference signal (ZP CSI-RS) resource sets for semi-persistent (SP) ZP CSI-RS, wherein each of the ZP CSI-RS resource sets includes a plurality of ZP CSI-RS resources, and the resource configuration information includes information about a periodicity and an offset for the SP ZP CSI-RS; transmitting, to the terminal, first information for enabling at least one ZP CSI-RS resource set for the SP ZP CSI-RS among the ZP CSI-RS resources; mapping resource elements for the downlink data based on the resource configuration information and the first information; and transmitting, to the terminal, the downlink data, wherein based on the enabling of the at least one ZP CSI-RS resource set, and based on the information about the periodicity and the offset for SP ZP CSI-RS, the downlink data is not mapped to the at least one ZP CSI-RS resource set, and wherein based on second information for disabling the at least one ZP CSI-RS resource set, the non-mapping of the downlink data to the at least one ZP CSI-RS resource set is ceased.
 16. The terminal of claim 9, wherein the operations further comprise: performing rate matching for the decoding of the downlink data based on the first information.
 17. The terminal of claim 9, wherein decoding the downlink data based on the resource configuration information and based on the first information comprises: decoding the downlink data based on the at least one ZP CSI-RS resource set being enabled for the SP ZP CSI-RS so as not to be available for reception of the downlink data. 